Standardization of humic acid with organic and inorganic fertilizers on growth, yield and economics of transplanted rice

Abstract

Integrated nutrient management approaches that substitute part of inorganic fertilizer inputs with organic and biostimulant sources have the potential to enhance nutrient-use efficiency and sustain crop productivity. A field experiment was conducted during kharif 2025 at the Agronomy Research Farm of Acharya Narendra Deva University of Agriculture and Technology, Kumarganj, Ayodhya, Uttar Pradesh, India, to evaluate the effects of humic acid and vermicompost in combination with reduced rates of recommended fertilizer dose (RDF) on the growth, productivity and profitability of transplanted rice. The experiment was laid out in a randomized block design with eight treatments, each replicated three times. Among the treatments, application of 75% RDF + 5 kg ha-1 humic acid at tillering + 2.5 t ha-1 vermicompost (T6) recorded the highest plant height (106.50 cm), tiller density (468.62 m-2), dry matter accumulation (1046.79 g m-2) and leaf area index (4.87), and was statistically comparable with 75% RDF + 2.5 kg ha-1 humic acid + 2.5 t ha-1 vermicompost (T4) for most growth and yield attributes. Treatment T6 also produced the highest grain yield (5621 kg ha-1) and net return (Rs.73,403 ha-1), whereas the maximum benefit ratio (1.35) was obtained with 75% RDF + 5 kg ha-1 humic acid (T5), primarily due to its lower cost of cultivation. Overall, the results demonstrate that integrating humic acid and vermicompost with 75% RDF can enhance rice growth and productivity while improving economic returns, offering a promising approach for reducing dependence on full rates of inorganic fertilizers.